AT89C5122 ATMEL [ATMEL Corporation], AT89C5122 Datasheet - Page 193

• Manufacturer Part Number: AT89C5122
• Description: MICROCONTROLLER WITH USB AND SMART CARD READER INTERFACES
• Manufacturer: ATMEL [ATMEL Corporation]

AC Parameters
Explanation of the AC
Symbols
External Program Memory
Characteristics
4202D–SCR–06/05
Each timing symbol has 5 characters. The first character is always a “T” (stands for
time). The other characters, depending on their positions, stand for the name of a signal
or the logical status of that signal. The following is a list of all the characters and what
they stand for.
Example:T
T
(Load Capacitance for port 0, ALE and PSEN = 60 pF; Load Capacitance for all other
outputs = 60 pF.)
Table and Table 118 give the description of each AC symbols.
Table 117 and Table 120 give for each range the AC parameter.
Table 115, Table 117 and Table 119 give the frequency derating formula of the AC
parameter for each speed range description. To calculate each AC symbols. take the x
value and use this value in the formula.
Example: T
x = 30 ns
T = 50 ns
T
Table 114. Symbol Description
A
CCIV
T
= -40°C to +85°C; V
Symbol
LLPL
T
T
T
T
T
T
T
T
T
T
T
= 4T - x = 170 ns
PLPH
PLAZ
LHLL
AVLL
LLAX
LLPL
PLIV
PXIX
PXIZ
AVIV
LLIV
T
= Time for ALE Low to PSEN Low.
AVLL
LLIV
Parameter
CPU clock period (F
ALE pulse width
Address Valid to ALE
Address Hold After ALE
ALE to Valid Instruction In
ALE to PSEN
PSEN Pulse Width
PSEN to Valid Instruction In
Input Instruction Hold After PSEN
Input Instruction Float After PSEN
Address to Valid Instruction In
PSEN Low to Address Float
= Time for Address Valid to ALE Low.
and 20 MHz, Standard clock.
SS
= 0V; V
CK_CPU
CC
)
= 3.6V to 5.5V ; F
CK_CPU
= 0 to 24 MHz.
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